Method and apparatus for making a self-aligning pillow block



July 6, 1965 c. HILTON METHOD AND APPARATUS FOR MAKING A SELF-ALIGNINGPILLOW BLOCK Filed April 16, 1962 INVENTOR. CARL HILTON United StatesPatent 3,192,667 METHED AND APPARA'EEJS FUR MAKiNG A SELF- ALEGNWGPTLLGW BLOCK Carl Hilton, Chicago, iii, assignor, by means assignments,

to Masten Corporation, (Zhicago, ill, a corporation of illinois FiledApr. 16, 1962, ar. No. 187,372 9 Gms. (Ci. 29l49.5)

This invention relates to the production of a novel pillow block.

More particularly the present invention relates to a new niethod andapparatus for making a self-aligning pillow b ock.

it is a particular object of the present invention to provide a novelmethod and apparatus for making a one-piece pillow block wherein thebearing is non-rotatably but pivotally retained therein wherebyself-aligning bearings are provided for journaling the ends of arotatable shaft.

It is a further object of the present invention to provide a method andmeans for casting a one-piece metal housing about a pre-formed bearingcomposed of elastic material and whereby after casting the bearingreadily separates from the housing to the extent that it can be pivotedwithin but not disengaged from the housing.

In general, the unit of the present invention comprises an inner bearingmember of elastic material such as sintered powdered metal having aspherical outer diameter and a cylindrical inner diameter or bore. Thespherical outside diameter of the bearing is substantially enclosed by arigid one-piece metal housing cast thereabout. The spherical outerdiameter of the bearing permits it to pivot within the rigid housing toallow for alignment of a shaft journaled in the bearing.

Large scale commercial production of a unit of the foregoing type hasbeen restricted at the present time, the basic problem therein beingcasting of a movable spherical insert into a rigid housing and tocompensate for the contraction of the housing on cooling. Without somemeans of compensating for this contraction, the insert is locked inplace and as a result cannot be pivoted. One method for compensating forthis contraction is to coat the insert with some material, such as alubricant, which will be dissipated either in the casting process orafterward. The prime reason for making the latter impractical forconsistent large scale commercial production is that of main taining auniform coating on the insert and controlling the dissipation of thecoating. Another disadvantage of the aforesaid method is that whensuificient coating is obtained for subsequent pivoting of the insert,some means must be introduced to keep the insert from spinning on itsaxis.

The difficulties of the prior practices are overcome by the presentinvention which employs a pre-formed bearing composed of elasticmaterial such as the aforesaid porous sintered powdered metalcomposition. Such porous sintered powdered metal material is elasticwithin limits and has properties of expansion and contraction and a highdegree of elasticity, and these properties are taken advantage of in thepresent invention.

Other objects and advantages of the present invention together with itsdetails of construction, arrangement of parts and economies thereof willbe apparent from a consideration of the following specification andaccompanying drawings, wherein:

FIG. 1 is a perspective view of a unitary pillow block formed inaccordance with the present invention, and wherein a bearing of thecharacter aforesaid is pivotally disposed and retained within aone-piece metal housing cast thereabout, the housing being of thetwo-bolt flange mounting type.

FIG. 2 is a section through a one-piece metal housing "ice cast aroundand in firm embracing engagement with a sintered powdered metal bearing.

FIG. 3 is a sectional view of a die component for compressing theunitary assembly of FIG. 2.

FIG. 4 is a section through the die of FIG. 3 showing the unit of FIG. 2compressed therein by means of a ram.

FIG. 5 is a section on the line 55 of FIG. 4.

FIG. 6 is a view showing the movement of a shouldered ram into thecavity of the die and contained pillow block assembly of FIG. 4.

FIG. 7 is a section on the line 77 of FIG. 6.

FIG. 8 is a section similar to that of FIG. 7 but with the pillow blockremoved from the ram and die components of FIG. 6.

Referring to the drawings, the reference numeral 10 generally indicatesa one-piece metal housing, for example, aluminum, cast about the bearinggenerally indicated at 11. The housing is formed with a pair of flanges12, 12 each having a hole 13 for reception of a mounting bolt. It will,of course, be understood that the illustrated pillow block unit is forthe purpose of illustration and not limitation. Thus, for example, thehousing may have a threebolt flange mounting, and in lieu of the axis ofthe bearing 11 being parallel to the axes of the bolt holes 13, f3, itwill be understood that the unit may be in the form of the standardmounting wherein the axes of the bolt holes 13, 13 are perpendicular tothe axis of the bearing 11. Of course, the flanges l2, 12 will then beat an angle of 90 to that shown in the illustration of FIG. 1.Alternatively the housing may be formed without attachment flanges sothat the outer surface of the portion which embraces bearing 11 iscylindrical and is later pressed into a cylindrical holder by the user.

The bearing 11, as employed in the present invention, is pre-formed ofconventional powdered metals, typical compositions of which are 90%copper and 10% tin; 77.5% copper, 7.5% tin and 15% lead; 25% copper andiron; 20% copper, 79.5% iron, and 0.5% carbon, and the like. A furtheralternative can be straight iron. These compositions are given for thepurpose of illustration and not limitation. The bearings are composed ofcompressed powders which are sintered in conventional manner to resultin compositions having a resilient sponge-like character. These areconventionally employed for selflubricating bearings in that they areporous and can contain approximately 25% of lubricating oil by volumestored in the tiny interconnected pores of the pro-formed bearing, thistype being known as an Oilite bearing.

As shown in FIG. 2, the bearing 11 is formed initially with acylindrical bore 14 and a spherical outer surface 15. In casting thehousing 19 about the bearing 11 in a suitable mold or die, not shown,the bearing 11 is first seated on a core pin and a one-piece housing 10cast thereabout.

As a result, the housing It? is formed with a mating spherical surfacebore 16. Desirably also and for facility in subsequent pivoting as willbe explained, the altitude of the spherical seat 16 of the housing It)is lessthan that of the spherical segment surface 15 of the bearing 11.

The housing material metal as it cools, shrinks tightly around thebearing 11. It will be understood that no coating has been employedbetween the outer surface of the bearing 11 and the cast face of thehousing 16 and.

ing pressure to the end of the bearing 11 in an axial direction and in afurther radial direction from inside the bore 14 of the bearing 11.

Thus, the unit as shown in FIG. 2 is forced into the cavity 17. of thedie 18 by means of a ram 19, the cavity of the die 18 being slightlysmaller than the outer dimensions of the housing 10. The reduction insize of the housing as a result of the aforesaid compression, is such as.to. maintain the metal of the housing 19 within its elastic limits sothat no permanent set is retained after removing the housing 10' fromthe die 18.

A shouldered punch 29 is then inserted into the bore 14 of the bearing11 until the shoulder 21 thereof, contacts an end of the bearing 11. Thepunch which is endwise tapered as at 22 has a diameter slightly largerthan that of the bore 14 so that it results in radial compression in anoutward direction and opposite to the radial compression resulting fromforcing the housing 10 into the die 18.

The shouldered punch is slightly out-of-round so that when forced intothe bearing 11 it induces in the latter a slightly out-of-round shapewhich is retained therein due to compression of the bearing 11 beyondits elastic limit.

Thus, when the punch 20 is removed from the bearing 11, and the housing10 is removed from the die 18, the housing 10 will return to itsoriginal size and contour but the bearing 11 will retain about 20% ofits compression and slightly out-of-round condition. This setcompression in the hearing, as a result of its resilient character,causes it to thereby separate from the confines of the spherical bore 14of the housing ltl but to be retained therein in a pivotal manner.Further due to the resulting out-of-round character of the bearing 11,it is prevented thereby from spinning within the housing 10. At the sametime, the strain of shrinkage of the housing 10 is relieved.

In a modified practice, the precast assembly of the housing 10 about thebearing 11 is forced into the cavity 17 of the die 18 in the mannerpreviously described. However, in this case the cavity 17 of the die isslightly out-of-round so that the housing 10 becomes temporarily pressedto out-of-round condition. Thereafter, a shouldered punch similar tothat of punch 21 is forced into the now slightly deformed bore 14 ofbearing 11. However, in this case the punch 20 is cylindrical in cross.

section, except for a slight taper. The diameter of the punch 26 is ofcourse slightly greater than that of the bore 14 in this modification sothat the outer surface of bearing 11 becomes deformed to an out-of-roundcondition since it is restricted by the out-of-r-ound compressed housingfrom expanding equally. The sintered powdered metal composition of thebearing 11 while being resilient and returning to some of its originalform, nevertheless does not return to its completely original form butremains with its outer surface deformed and out-of-round. Thus, while itbecomes in this operation separated from the housing 10, it isnevertheless retained therein in a pivotal manner, firstly by thehousing 10, and secondly is retained against spinning on its axis byreason of its out-of-round character and relatively small degree ofseparation from the confines of the housing 10.

In another modified method, similar but not fully equivalent results maybe accomplished with or without restraining the housing 10. In thiscase, the die 18 having a cavity 17 may be employed but wherein thecavity 17 is of equal dimension to the outer diameter of the housing 10so that it merely forms a seat therefor. In the alterna tive, otherholding means may be employed. In this modified method, the sinteredpowdered metal bearing 11 only is compressed by restraining its axialmovement at one end by means of, for example, the die 18, or othermeans, and a shouldered punch similar to punch 29 of slightly largerdiameter than the inside diameter of the bore 14 is forced into thebearing 11. This compresses the bearing to a degree beyond its elasticlimit and when the punch is withdrawn the bearing will spring backsufiiciently to relieve the restraining force of the compression of thehousing It) and separate itself from the housing. In this case, thehousing and bearing remain round, but the amount of expansion andspring-back is controlled to retain sufficient friction of the bearing14 against the confines of housing 10 so as to prevent the bearing 11from spinning on its axis While remaining pivotally retained in thehousing 10.

However, due to the pivotability of the bearing 11 within the housing 10in each case, it is possible to corn pensate for initial or subsequentminor misalignment of a shaft journaled in the bearing 11 and to therebyrelieve undue stress on either the bearing or the shaft or both. Thehousing It needs only to be bolted in place by means of suitable boltsengaged through the holes 13 in the integral flanges 12 to provide abearing surface for a rotatable shaft. Thus, the device of the presentinvention provides a self-aligning bearing surface with a simple meansby fastening the bearing to a suitable support and eliminates the needfor costly alignment since the unique construction and arrangement ofthe parts automatically provides for self-alignment and the assemblyrelieves undue stress of the engaged rotating shaft in the bearingthrough application of a ball-joint-like unit.

Although I have shown and described the preferred embodiment of myself-aligning pillow block and preferred method and means for formingthe same, it will be understood by those skilled in the art that variouschanges may be made in the details thereof without departing from thespirit and scope of my invention as comprehended by the followingclaims.

I claim:

1. The method of making a self-aligning pillow block which comprisescasting a onepiece rigid metal housing about a bearing composed ofelastic sintered powdered metal material having a spherical outersurface and formed with a cylindrical axial bore to provide said housingwith a spherical bore partially embracing and retaining. said bearing,and then subjecting said bearing to radial compression outwardly fromwithin its bore to cause it to become fixedly compressed, and thenremoving said compressing forces to cause said bearing to becomeslightly separated from the internal surface of the housing whileremaining pivotally disposed therein and frictionally retained againstrotation on its axis.

2. The method of making a self-aligning pillow block which comprisescasting a one-piece rigid metal housing about a bearing composed ofelastic sintered powdered metal material having a spherical outersurface and formed with a cylindrical axial bore to provide said housingwith a spherical bore partially embracing and retaining said bearing,thereafter compressing said housing, Within its elastic limit, aboutsaid bearing to radially compress the latter, and then while socompressed further subjecting said bearing to radial compressionoutwardly from within its bore to cause it to become fixedly compressed,and then removing said compression forces.

3. The method of forming a self-aligning pillow block which comprisesradially compressing to out-of-round contour a bearing composed ofelastic sintered powdered metal material initially having a sphericalouter surface and formed with a cylindrical bore while disposed in aonepiece rigid metal housing cast thereabout having a spherical bore oflesser altitude than that of said bearing surface, and thereafterpermitting said bearing to expand and to but partially return to itsoriginal contour and to thereby become spaced from and pivotallydisposed within said housing while frictionally retained therein againstspinning on its axis.

4. The method of forming a self-aligning pillow block which comprisesdisposing a bearing composed of elastic sintered powered metal materialhaving a spherical outer surface and formed with a cylindrical bore overa core pin having a cylindrical outer diameter snugly seating saidbearing, casting a one-piece rigid metal housing about said bearing toprovide said housing with a spherical bore of lesser altitude than thatof said bearing surface, thereafter withdrawing said core pin,compressing said housing to deform its spherical bore to out-of-roundcondition, within its elastic limit, about said bearing to radiallycompress the latter, then while so compressed subjecting said bearing toaxial compression outwardly from within its bore to cause it to becomefixedly compressed into a slightly out-of-round controur, and thereafterremoving the compressing forces to permit the housing to fully return toits original contour and the bearing to but partially do so and tothereby become spaced from while remaining in pivotal disposition withinsaid housing.

5. The method of forming a self-aligning pillow block which comprisesdisposing a bearing composed of elastic sintered powdered metal materialhaving a spherical outer surface and formed with a cylindrical bore overa core pin having a cylindrical outer diameter snugly seating saidbearing, casting a one-piece rigid metal housing about said bearing toprovide said housing with a spherical bore of lesser altitude than thatof said bearing surface, thereafter withdrawing said core pin,compressing said housing, within its elastic limit, about said bearingto radially compress the latter, then while so compressed subjectingsaid bearing to axial compression and to further uneven radialcompression outwardly from within its bore to cause it to become fixedlycompressed into a slightly out-of-round contour, and thereafter removingthe compressing forces to permit the housing to fully return to itsoriginal contour and the bearing to but partially do so and to therebybecome spaced from while remaining in pivotal disposition within saidhousing.

6,. Means for forming a self-aligning pillow block wherein a one-piecemetal housing is case about a preformed sintered powdered metal bearingformed with a. cylindrical bore and a spherical outer surface,comprising a die for radially compressing the housing about the bearing,and a punch for disposition within said bearing to resiliently radiallyexpand it to slightly out-of-round condition.

7. Means for forming a self-aligning pillow block wherein a one-piecemetal housing is case about a preformed sintered powered metal bearingformed with a cylindrical bore and a spherical outer surface, comprisinga die for radially compressing the housing to out-ofround contour aboutthe bearing, and a punch for disposition within said bearing toresiliently radially expand it to said slightly out-of-round contour.

8. Means for forming a self-aligning pillow block wherein a one-piecemetal housing is cast about a preformed sintered powdered metal bearingformed with a cylindrical axial bore and a spherical outer surface,comprising a die formed with a cavity for radially compressing thehousing about the bearing, within the elastic limit of the housingmetal, and a shouldered punch for disposition within said bearing toaxially compress it and to further radially expand it beyond its elasticlimit.

9. The method of making a self-aligning pillow block which comprisescasting a one-piece rigid metal housing about a bearing composed ofelastic sintered powdered metal meterial having a spherical outersurface and formed with a cylindrical axial bore to provide said housingwith a spherical bore partially embracing and retaining said bearing,and then subjecting said bearing to axial compression to cause it becomefixedly compressed, and then removing said compressing forces to causesaid bearing to become slightly separated from the internal surface ofthe housing while remaining pivotally disposed therein and frictionallyretained against rotation on its axis. t

References Cited by the Examiner UNITED STATES PATENTS 2,626,841 1/5 3Potter 30872 2,728,975 1/ 5 6 Potter.

2,894,789 7/59 Tracy 308-72 2,997,775 8/ 61 Pennala.

WHITMORE A. WILTZ, Primary Examiner.

FRANK SUSKO, Examiner.

1. THE METHOD OF MAKING A SELF-ALIGNING PILLOW BLOCK WHICH COMPRISESCASTING A ONE-PIECE RIGID METAL HOUSING ABOUT A BEARING COMPOSED OFELASTIC SINTERED POWERED METAL MATERIAL HAVING A SPHERICAL OUTER SURFACEAND FORMED WITH A CYLINDRICAL AXIAL BORE TO PROVIDE SAID HOUSING WITHSPHERICAL BORE PARTIALLY EMBRACING AND RETAINING SAID BEARING, AND THENSUBJECTING SAID BEARING TO RADIAL COMPRESSION OUTWARDLY FROM WITHIN ITSBORE TO CAUSE IT TO BECOME FIXEDLY COMPRESSED, AND THEN REMOVING SAIDCOMPRESSING FORCES TO CAUSE SAID BEARING TO BECOME SLIGHTLY SEPARATEDFROM THE INTERNAL SURFACE OF THE HOUSING WHILE REMAINING PIVOTALLYDISPOSED THEREIN AND FRICTIONALLY RETAINED AGAINST ROTATION ON ITS AXIS.